Re: Cold Cathode Transformer

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Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Phil,

Yes, sorry, I should have stated florescent as opposed to neon when 
referring to electrode heating (hot cathode). Neon and cold cathode 
have the same technology, but typical neon lighting versus cold 
cathode lighting is tube size and current requirements. Also, the 
smaller tube (<15mm) "neon" electrode I believe has a coating on the 
electrode to aid electron emission. The main difference I see is neon 
lighting is for making decorative signs of light, whereas, "cold 
cathode lighting" is just that, "lighting", or very bright decorative 
signs. It's the cold cathode lighting manufacturers who are actually 
creating a defining difference. Neon is just not bright enough to be 
used for a light source, but their higher current "cold cathode" brothers can.

Take care,
Bart

> I thought all neon lighting was cold cathode? I know some 
> fluorescents are cold cathode - are these what you're thinking of? 
> Not sure why anybody would want to dim neon (although a friend of 
> mine did so for a display in his house, using a variac).
>     15kV seems like an awful lot of voltage to start a fluorescent 
> bulb - don't they all contain, by definition, mercury vapor that 
> the neon tube lacks?
>     120mA also seems on the a low side of running current for even 
> a single fluorescent bulb?
>
> -Phil LaBudde